Photographic elements



Dec. 28,1954 F. E. SWINDELLS 2,698,235

PHOTOGRAPHIC ELEMENTS Filed March 16, 1950 GELATIN AND SILVER HALIDE GELATIN VINYLIDINE CHLORIDE ACRYLONITRILE lTA omc ACID OPO Y- 2 CELLULOSE ACETATE c C M ER 2 GELATIN 8 GELATIN AND SILVER HALIDE G E L A T I N 6 VINYLIDINE CHLORIDE/METHYL ACRYLATE/ITACONIC ACID COPOLY- 5 POLYETHYLENE TEREPHTHLATE R g GELATIN AND SILVER HALIDE VINYLI DENE CHLORIDE/METHYL ACRYLATE/ITACONIC ACID CO- BARYTA COATING POLYMER PAPE R m Ti0 sio m VINYLIDENE CHLORIDE/METHYL ACRYLATE/ INVENTOR FRANK E. SWINDELLS ATTORNEY United States Patent 2,698,235 PHOTOGRAPHIC ELEMENTS Frank E. Swindells, Maplewood, N.J., assignor t E. 'L du Pont de Nemours and Company, Wilmington, De]., a corporation of Delaware Application March 16, 1950, Serial No.'150,11'3 14 Claims. (Cl. 95-8) This invention relates to -photographic film elements. More particularly it relates to transparent photographic film elements which have an improved anchoring substratum between the film base and the water-permeable colloid layer or layers disposed thereon. .Still moreparticularly, it relates to photographic elements which have good dimensional stability and a novel anchoring ssubstratum composed of a copolymer of vinylidene chloride, an acrylic ester and itaconic acid. zlnapreferred embodiment it relates to a dimensionally .stable photographic film element having a film base composedof a highly polymeric linear ester of a dicarboxylic 'acid and a dihydric alcohol and at least one water permeable colloid layer anchored to thebaseby means'of a-copolymer of vinylidene chloride, an acrylic ester and'itaconic acid.

it is common practice in themanufacture of photographic films to apply a thin substratum of gelatin from a dispersion in a solvent for the film -b'ase'before the light-sensitive silver halide emulsion layer "is applied. If this anchoring substratum is .omitted or iis applied from a non-solvent for the base, the photographic emulsion layer will not adhere with .sufiicient tenacity to the base. It is also knownto provide a photographic film base such as a cellulose acetate film with a thin layer of a resin in order to improve thiswater resistance. .An anchoring substratum of gelatin is generally'coated upon the thin resin layer or a thinnitrocellul'ose layer from a dispersion in a solvent for such'layer beforethe'gelatino silver halide emulsion layeris coated.

An object of thisinvention is'to provide photographic film elements with improved anchoring 'substrata. A further object is to provide photographic elements'with improved dimensional stability and anchorage between the film base and water-permeable colloid layers disposed thereon. A still further object of the invention is to provide an anchoringsubstratum which will eliminate the usual gelatin sublayer. Another objectis to provide a photographic element with a novel anchoring substratum which also confers dimensional stability upon the film base. the following description of the invention.

It has been found that if-a photographic support including paper and film base which is composed of a hydrophobic material, e. g., a hydrophobic cellulose carboxylic acid ester including cellulose acetate, cellulose acetate butyrate, cellulose nitrate; a superpolymer, -e. g., a superpolyamide (nylon), a highly polymeric linear ester of a dicarboxylic acid and a dihydric alcohol,.polyvinyl chloride, etc., is coated with a copolymer of vinylidene chloride, an acrylic ester and itaconic acid that the resulting layer has excellent adherence to the film base and what is more important adheres tenaciously to a water-permeable colloid layer which is deposited thereon, e. g., gelatino-silver halide emulsion layer, a gelatin filter layer or an antihalation layer containing 'awaterpermeable colloid binding agent.

In order that the 3-component copolymers in -question will have an adequate degree of adherenceto thefilm base and the requisite degree of moisture-proofness and flexibility, it is essential that the initial relative proportions of monomers in the reaction mixture be within the following ranges:

Still other objects will be apparent from .methods.

' technique. solution. or from aqueous dispersion.

2,698,235 Patented Dec. 28, 1954 The *useful acrylic esters which may be used in the -copolymers are the alkyl esters of acrylic "and methacrylic acids having from 1 to 18 carbon atoms in the 'alkyl butyl methacrylate, octyl methacrylate,.n-dodecyl methacrylate, n-octadecyl methacrylate, methyl acrylate, ethyl acrylate and propyl acrylate; vinyl chloride, acrylonitrile and .methacrylonitrile.

The monomers may be copolymerized by various For example, the copolymerization .may be conducted in aqueous dispersion containing a catalyst and activator, e. g., ammonium persulfate and.meta sodium bisulfite, and an emulsifying and/or dispersing agent. Alternatively, the copolymers of this invention may be prepared by polymerization of themonomeric components'in-bulk without added diluent, or the monomers may be reacted 1n appropriate organicsolvent reaction media. The total catalyst-activator concentration should generally be kept within a range of=about'0.0l%

to about 2.0% by weight of the-monomer charge, and preferably within a range of concentration of 0.1% to 1.0%. Improved solubility and viscosity values'are obtained by conducting the polymerization in the presence :of mercaptans-such as ethyl mercaptan, lauryl mercaptan, tertiary dodecyl mercaptan, etc., which are'efiective in reducing cross-linking in the copolymer. In general,

the mercaptans should be used in concentrations of 0. l% -to 5.0% by weight, based on the weight of polymerizable monomers present in the charge.

The copolymers of this invention can be coated on the hydrophobic film base or support by any suitable They maybe applied as anorganic solvent In a preferred aspect of theinvention,'the novel photographic films have a base which is composed of a highly polymeric linear ester of a dicarboxylic acidvand a dihydric alcohol. Photographic film elements having high polymeric linear ester film bases have been proposed and are described in Carothers U. S. Patent 2,216,- 736. These esters are crystalline and have a relatively high melting point. Fibers formed by cold drawing these esters show molecular orientation along the fiber axis by characteristic X-ray patterns. It has been found that such polyester film bases while having the various advantages described 'in the patent have the disadvantage that it is diflicult to obtain an adequate degree of permanent adherence between the base and a superimposed colloid silver halide emulsion layer, particularly with multilayer color films with lengthy treatment Lin aqueous' processing solutions. It is generally necessary .to first apply a gelatin substratum to the film base before applyinga gelatin silver halide emulsion. It has been found, however, that when film base vis provided with a substratum of the 3-component copolymers described above and coated with a gelatino-silver halide emulsion layer one obtains good anchorage.

The itaconic acid component is an essential and importantpart of the copolymer used in the substratum. It has .beenfound that this acid is unique since related acids such .as aconitic or maleic, when substituted in similar amounts, .give entirely ditferentresults. The copolymers containing the latter acids have poor adherence to water-permeable colloidlayers-and gelatino-silverhalide emulsion layers, e. g., gelatin. .Itaconic acid esters, e. g., dimethyl itaconate, likewise when substituted for itaconic acid result in layers "having different properties. The substitution results in..a

The invention'will be further illustrated but is not intendedto be limited by the following examples.

Example 1 A vinylidene chloride-methylacrylate-itaconic acid copolymer is made by admixing the following constituents in a reaction vessel:

*A mixture of sodium n-alkyl sulfates of 8 to 16 carbon atoms predominating in sodium n-dodecyl sulfate. The reaction vessel is heated to about 34 C. and stirring continued until the vinylidene chloride is all consumed, as indicated by cessation of reflux. The time required is about 1 hour, 50 minutes. At this point one gram of the condensation product of sodium fl-naphthalene sulfonate and formaldehyde is stirred in, the emulsion cooled and filtered.

A strip of cellulose nitrate film was drawn through the vinylidene copolymer dispersion, drained and allowed to air dry, at which time the coating appeared as a clear, continuous layer. After curing at 100 C. for minutes, a 2% water solution of gelatin was applied, allowed to dry over night and cured at 100 C. for ten minutes. The film was then coated with a gelatino silver halide emulsion and dried. The anchorage between the cellulose nitrate and the copolymer was adequate and between the latter and gelatin good.

A copolymer made in the identical manner with the itaconic acid omitted, gave very poor anchorage, the failure being at the gelatin/copolymer interface.

Example 2 The following mixture was placed in a reaction vessel, stirred and refluxed as in Example 1.

The reaction was complete in about six hours. The emulsion was poured into about 1000 grams of solution of aluminum ammonium sulfate with stirring, washed free of sulfate, washed once with methanol and dried at 50-70 C. About 80 grams of a white resinous copolymer, which was soluble in acetone, methyl ethyl ketone, and dioxane was recovered.

A 4% solution of the above 3-component copolymer by weight in acetone was applied to a cellulose acetate film 1 from a bead applicator to form a layer 2 of copolymer and the coated film then dried in air. A similar layer 2 was coated on the opposite surface of the base and dried in like manner. An aqueous gelatin dispersion containing the following ingredients was applied to the surface of each layer of copolymer to form layers 3 and the film was then cured at 100 C. for 30 minutes:

Parts Gelatin 1 Water 2 Salicylic acid 0.5 Methanol 60 Denatured ethyl alcohol formula 2B 36.5

To 100 gallons of 190 proof ethyl alcohol is added 0.5 gallon of benzene.

and given the same treatment as above except that the following gelatin dispersion was substituted:

Parts Gelatin 1 Water 1 Salicylic acid 0.5 Methanol 37.5 Acetone 60 The photographic emulsion did not anchor as well to this base, the failure being between the gelatin substratum and the copolymer.

Example 3 The following materials are placed in a flask and processed as in Example 1:

Grams Vinylidene chlor 75 Ethyl acryl 25 Itaconic acid 2 Water 100 Sodium dodecyl sulfate mixture (see Example 1)- 2 Ammonium persulfme 0.33 Sodium metabisulfite 0.17

Example 4 A dispersion is prepared similar to that of Example 1, but containing grams vinylidene chloride, 15 grams methyl acrylate and 2 grams itaconic acid. A strip of cellulose triacetate film 8 mils thick is drawn through this dispersion allowed to drain, air dried and cured ten minutes at C. It is then coated with dilute aqueous gelatin, again cured, and coated with a gelatino silver halide emulsion. Good adhesion is obtained between all ayers.

Example 5 A strip of nylon film (polyhexamethylene adipamide) having a thickness of 5 mils is given the same treatments as the cellulose triacetate in Example 4. An adequate degree of anchorage between the gelatin silver halide emulsion layer and the coated base is obtained.

Example 6 A strip of an unstretched sheet of an ethylene glycolterephthalic acid copolymer having a melting point of more than 200 C. of the type described in U. S. Patent 2,465,319 is given the same treatments as the cellulose triacetate in Example 4. A high degree of anchorage of the gelatin and silver halide emulsion layer to the coated film base is obtained.

Example 7 A strip of a vinyl chloride/vinylacetate copolymer film having a thickness of 8 mils is coated with a layer of the 3-component copolymer and the remaining layers after the manner described in Example 6. A good degree of anchorage of the silver halide emulsion layer to the coated base is obtained.

Example 8 The 3-component copolymer described in Example 2 is made up into a 4% solution in methyl ethyl ketone, and applied to 3-mil cellulose acetate film base with a bead coater. When dry, gelatin and gelatino silver halide layers are applied as in Example 2, the anchorage is found to be excellent.

. Example9 The following materials were heated to approximately 35 C. in a three-neckflask fitted with astirrer and a reflux condenser:

Grams Vinylidene chloride '188 Methyl acry1ate 12 Itaconic acid v 4 Water 200 Ammonium persulfate 0.7 Sodiummetabisulfite 0.35 Sodium dodecyl sulfate mixture (see Example 1)--.. 4

The stirring was continued'until the refluxing of the vinylidene'chloride had stopped. At this point 4 grams ofsodium ,B-naphthalene sulfonate formaldehyde condensation product dissolved in water were added and the copolymer dispersion was cooled. One 'part'of the copolymer dispersion was diluted with three parts of Water. Sufficient of the sodium alkylsulfate mixture described above was added to the diluted dispersion to promote good wetting of the :polyester film base surface (approximately 5 cc. of

A strip of unstretched polyester film 5 of the kind described in Example 9 was coated with an aqueous dispersion of the copolymer described in that example. After the surface of the layer 6 of copolymer had dried, a 2% solution of gelatin in water was applied to form sublayer 7. The coated strip was then heated at 100 C. and an aqueous gelatino silver halide emulsion was applied to form a light-sensitive layer 8. The emulsion adhesion was good both While wet after photographic processing and dry before and after.

Example 11 The following materials were heated to approximately 35 C. in a three-neck flask, fitted with a stirrer and a reflux condenser:

Grams Vinylidene chloride 170 Methyl acrylate 30 Itaconic acid 4 Water 200 Ammonium PCISLllf'lte 0,7 Sodium metabisulfite 0.35 Sodium dodecyl sulfate mixture (see Example 1) 4 The stirring was continued until the refluxing of the vinylidene chloride had stopped. At this point 4 grams of sodium fi-naphthalene sulfonate-formaldehyde condensation product dissolved in water were added and the emulsion was cooled.

One part of the copolymer dispersion was diluted'with three parts of water. Sufficient of the sodium dodecyl sulfate mixture was added to the diluted emulsion to promote good wetting of the surface of a film of the type in Example 6 (approximately 5 cc. of a 5% aqueous solution per 100 cc. of emulsion). The dispersion was then applied to unstretched polymer film of the type described in Example 6. After drying and seasoning at 100 C., the film was coated with a gelatino silver halide emulsion. There was adequate adhesion betweenthe film base and the emulsion layer.

Example 12 A strip of unstretched polyester film of the type in Example 9 was coated with an aqueous dispersion of the copolymer described in Example 11. After the surface of the copolymer had dried, a 2% solutionof gelatin in Water was applied. The treated film was heated at 100 C. and gelatino silver iodobromide emulsion was applied. Emulsion adhesion was good.

Example 13 A strip of film of the kind in Example 9 was laterally and longitudinally stretched to obtain a finished film haviiig2% times :its original dimensions in both-directions to orient tlie same and then treatedwith a 4% diox-ane 6 solution of the 3-component copolymer described in Example 11 (coagulated, washedanddried After the copolymer surfacehad dried,.a 2% solution of gelatin in water was applied. The treated strip was heated 'at C. and a gelatino silver iodobromide emulsion'was applied. Emulsion adhesion was good.

Example :14

A strip of stretched film of the kind in Example 9 was treated with the dioxanesolution ofthe =3-component copolymer described in Example 13. After the surface of the layer of'copolymer had dried, a gelatin substratum was applied from the following solution:

Per cent Gelatin 1.0 Water 1.0 Salicylic acid. 05 Methanol 97.5

The sample was heated at 100 C. and a gelatino silver iodobromide emulsion was applied. Emulsion adhesion was good.

Example 15 Example 16 Astrip of stretched filmof the kind in Example 9 was treated with a 4% dioxane solution of a copolymerof vinylidene chloride prepared just as the copolymer of Example 11 except that only'0'.5 gram of itaconic'acid was used. After the copolymer surface had dried, a 2% solution of gelatin in water was applied. "The treated film was heated at 100 C. for 15 minutes "and was then coated with a gelatino silver iodobromide emul sion. The emulsion adhesion was good.

Example 17 A strip of biaxially stretched film of the kind in Example 13 was treated with a 4% dioxane solution of a copolymer of vinylidene chloride prepared *just as the copolymer of Example 11 except that 8 grams of itaconic acid were used. After the surface-of the'copolymer had dried, a 2% solution of gelatin in water was applied. The treated strip was heated at 100 C. for 15 minutes and a gelatino silver iodobromide emulsion was applied. Emulsion adhesion was good.

Example 18 A vinylchloride/vinylacetate copolymer film was coated with an aqueous dispersion of a 'copolymer of vinylidene chloride of the type described in Example 9 to form a thin layer. After drying, the film wastreated with a 2% aqueous solution of gelatin, heated at 100 C. for 15 minutes and coated with a gelatino silver iodobromide emulsion. The adhesion was fair.

Example 19 A sheet of transparentized paper (impregnated with a copolymer obtained by polymerization of "an ethylene glycol dimethacrylate in situ) was coated'with an'aqueous dispersion of a 3-component copolymer'of vinylidene chloride of the type described in Example 11. After drying, the copolymer layer was coated with a 2% aqueous solution of gelatin, heated at 100 C. for-15 minutes and coated with a gelatino silver iodobromide emulsion. Adhesion of the gelatin and silver halide emulsion layers was good.

Example 20 A sheet 9 of paper having a baryta coating 9' was treated with an aqueous dispersion of a copolymer-of vinylidene chloride of the type described in Examplelll. After heating at 100 C. for 15 minutes,'the layer-100i copolymer was coated with a gelatino silver halide 7 emulsion to form layer 11. The emulsion adhesion was good and the resistance to moisture of the paper thus treated was excellent. It is not necessary to have a separate gelatin substratum. This is advantageous in the manufacture of photographic paper.

Example 22 A sheet of white, smooth finish bristol board (weight 300 pounds per thousand sheets 22.5 by 35 inches) was treated in the same fashion as in Example 21. The emulsion anchorage was again excellent.

Example 23 A pigment dispersion was made by admixing the following components:

Parts Titanium dioxide 100 Diatomaceous silica 0 Sodium fl-ethylnaphthalene sulfonic acid-formaldehyde condensation product 2 Water 250 The above components were mixed together and ground in a ball mill for about 20 hours whereby the pigments acquired a very small particle size. A mixture of equal parts by weight of this pigment dispersion and the vinylidene chloride copolymer dispersion of Example 1 was prepared and allowed to stand for a period of 16 to 24 hours. The stable dispersion was then coated on both sides of a continuous sheet of bond paper 12 forming pigmented layers 13, the type described in Example 21, by the aid of a skim coating device at a temperature of 140 C. and a speed of 2 feet per minute and dried. A gelatino silver iodobromide emulsion was coated onto the layer of copolymer and dried. The emulsion layer 14 had excellent anchorage to the pigmented copolymer layer.

The copolymer and gelatin sublayers may be deposited on the support or film base by any of the conventional methods used in the manufacture of photographic elements, e. g., by immersion of the surfaces of the film into a solution of the coating material, spraying, beading or coating from a hopper provided with a doctor blade, etc.

The thickness of the layer may vary over a fairly wide range, e. g., 0.05 mil to 1.0 mil or more. In general, however, from 0.1 to 0.2 mil coatings will be most useful.

Various wetting or dispersing agents can be used in place of those described in the foregoing examples wherein the layer of copolymer is applied from an aqueous dispersion.

The dispersions can be obtained directly from the polymerization reaction medium when the copolymer is made by emulsification polymerization technique. They may contain various wetting and dispersing agents, e. g., n-alkane sulfonic and sulfuric acid alkali metal, ammonium and amine salts of 10 to 18 carbon atoms, the

methyl, ethyl and isopropyl naphthalene sulfonic acid I alkali metal salts, etc. From 0.05 to 2% by weight of the dispersing agent is generally sufiicient.

The invention is not limited to the particular lightsensitive silver halides described above. Thus, the lightsensitive layers may be composed of simple or mixed silver halides dispersed in various types of waterpermeable binding agents. Thus, the coatings may contain silver chloride, silver bromide, silver-chlorobromide and silver-iodobromide in gelatin or equivalent waterpermeable colloids.

When organic solvent solutions of the copolymer are used for coating the layer of copolymer a volatile solvent is preferable and thus should be one which will bite into the film support. Among the useful additional solvents are methyl propyl ketone, methyl isobutyl ketone and butyl acetate and mixtures of such solvents. Ethyl acetate can also be used with such solvents.

These substrata are not necessarily used alone to join the support and light-sensitive layer, but may, if desired, be used in conjunction with other substratum layers such as gelatin, water-sensitive cellulose esters, water-proofing layers, anti-halation layers, and filter layers. Also, it is possible to incorporate removable or bleachable silver and anti-halation dyes in these layers.

The photographic film elements of this invention have wide application in the general field of photography and have various advantages due to their good dimensional stability and the adherence of water-permeable colloid layers to the novel anchoring copolymer substrata. Multilayer color films using the substrata are especially useful since the substrata contain no migratory of volatile acidic compounds which can cause fading of the colors. Lithographic films and X-ray films made by depositing one or more gelatino silver halide emulsion layers on a hydrophobic support coated on each side with the copolymer layers described above have good dimensional stability. In photographic papers the tri-component copolymer layer or layers which can be on each side of the paper sheet impart excellent water-proofing properties and at the same time give excellent adherence to a gelatino silver halide emulsion layer. The need for a separate gelatin sublayer is eliminated with consequent economies in manufacturing.

As many widely different embodiments of this invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

l. A photographic element comprising a sheet of paper having on at least one surface a layer of a tri-component copolymer made from 35 to 96% of vinylidene chloride, 3.5 to 40% of acrylonitrile and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, and a water-permeable gelatin silver halide layer deposited on a said layer of copolymer.

2. An element as set forth in claim 1 wherein said sheet is bristol board.

3. A photographic element comprising a baryta coated sheet of paper having on the baryta surface a layer of a tri'component copolymer made from 35 to 96% of vinylidene chloride, 3.5 to 40% of acrylonitrile and 0.5 to 25% of itaconic acid monomers, ail percentages being by weight, and having a gelatin silver halide layer deposited on a said layer of copolymer.

4. A photographic film element comprising a transparent, hydrophobic film base having on at least one surface a layer of a tri-component copolymer made from 60 to 94% of vinylidene chloride, 5 to 35% of acrylonitrile and 1 to 5% of itaconic acid monomers, all percentages being by weight, having a layer of gelatin on said layer of copolymer and having a gelatin silver halide layer on said layer of gelatin.

5. A photographic film element comprising a hydrophobic cellulose carboxylic acid ester film base having on at least one surface a layer of a tri-component copolymer made from 60 to 94% of vinylidene chloride, 5 to 35% acrylonitrile and 1 to 5% of itaconic acid monomers, all percentages being by weight, having a thin gelatin layer on a said layer of copolymer and having a gelatino silver halide emulsion layer on said gelatin layer.

6. A photographic film element comprising a film base composed of a highly polymeric ester of ethylene glycol and terephthalic acid having a melting point above 200 C. having on at least one surface a layer of a tri-component copolymer made from 60 to 94% of vinylidene chloride, 5 to 35% of acrylonitrile and l to 5% of itaconic acid monomers, all percentages being by weight, having a thin gelatin layer on a said layer of copolymer and having a gelatino silver halide emulsion layer on said gelatin layer.

7. A photographic element comprising a sheet of paper having on at least one surface a layer of a tri-component copolymer made from 35 to 96% vinylidene chloride, 3.5 to 40% of acrylonitrile and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, which has uniformly dispersed therethrough a finely divided white pigment and having a gelatino-silver halide emulsion layer on said layer of copolymer.

8. A photographic element comprising a support in the form of a sheet having on at least one surface a layer composed of a tri-component copolymer made from 35 to 96% of vinylidene chloride, 3.5 to 40% of an ethylenically unsaturated ester and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, said ester being taken from the group consisting of alkyl esters of acrylic and methacrylic acids having 1 to 18 carbon atoms in the alkyl group, acrylonitrile, methacrylonitrile and vinyl chloride and having a gelatin layer on a said layer of copolymer, said element containing at least one gelatin stratum containing light-sensitive silver halides adjacent said layer of copolymer.

9. A photographic element comprising a transparent, hydrophobic film base having on at least one surface a layer composed of a tri-component copolymer made from 35 to 96% of vinylidene chloride, 3.5 to 40% of an ethylenicallv unsaturated ester and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, said ester being taken from the group consisting of alkyl esters of acrylic and methacrylic acids having 1 to 18 carbon atoms in the alkyl gyroup, acrylonitrile, methacrylonitrile and vinyl chloride and having a gelatin layer on a said layer of copolymer, said element containing at least one gelatin stratum containing light-sensitive silver halides adjacent a said layer of copolymer.

10. A photographic element as set forth in claim 9 wherein said base is composed of a polyethylene terephthalate having a melting point above 200 C.

11. A photographic film element comprising a transparent, hydrophobic film having on at least one surface a layer composed of a tri-component copolymer made from 35 to 96% vinylidene chloride, 3.5 to 40% of an ethylenically unsaturated ester and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, said ester being taken from the group consisting of alkyl esters of acrylic and methacrylic acids having 1 to 18 carbon atoms in the alkyl group, acrylonitrile, methacrylonitrile and vinyl chloride, at gelatin layer deposited on said layer of copolymer, and a gelatin silver halide emulsion layer of said gelatin layer.

12. A protographic film element comprising a transparent, hydrophobic film having on at least one surface a layer composed of a tri-component copolymer made from 35 to 96% vinylidene chloride, 3.5 to 40% of an ethylenically unsaturated ester and 0.5 to 25% of itaconic acid monomers, all percentages being by weight, said ester being taken from the group consisting of alkyl esters of acrylic and methacrylic acids having 1 to 18 carbon atoms in the alkyl group, acrylonitrile, methacrylonitrile and vinyl chloride, and a gelatin silver halide emulsion layer deposited on said layer of copolymer.

13. A photographic element comprising a sheet of transparent film composed of a polyethylene terephthalate having a melting point above 200 C., having on at least one surface a layer composed of a tri-component copolymer made from to 94% of vinylidene chloride, 5 to 35% of an alkyl ester of acrylic acid wherein said alkyl group contains from 1 to 18 carbon atoms and 1 to 5% of itaconic acid monomers, all percentages being by weight, a layer of gelatin on said layer of copolymer, said element having at least one gelatin stratum containing light-sensitive silver halides adjacent said layer of copolymer.

14. A photographic element as set forth in claim 13 wherein said alkyl ester of acrylic acid is methylacrylate.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,047,398 Voss et al July 14, 1936 2,204,608 McNally et al June 18, 1940 2,244,703 Hubbuch June 10, 1941 2,329,456 Campbell Sept. 14, 1943 2,391,621 Powell et al. Dec. 25, 1945 2,491,023 Alles et al Dec. 13, 1949 2,570,478 Pitzl Oct. 9, 1951 FORElGN PATENTS Number Country Date 614,932 Great Britain Dec. 30, 1948 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SHEET OF PAPER HAVING ON A LEAST ONE SURFACE A LAYER OF A TRI-COMPONENT COPOLYMER MADE FROM 35 TO 96% OF VINYLIDENE CHLORIDE, 3.5 TO 40% OF ACRYLONITRILE AND 0.5 TO 25% OF ITACONIC ACID MONOMERS, ALL PERCENTAGES BEING BY WEIGHT, AND A WATER-PERMEABLE GELATIN SILVER HALIDE LAYER DEPOSITED ON A SAID LAYER OF COPOLYMER. 